Details of adsorption of olefin molecules in the micropores of zeolites are revealed by using low-temperature IR spectroscopy. The well-known π-adsorption of olefins was found to be an activation process from the weaker adsorption with alkyl-acidic OH (OD) interaction, which was in equilibrium with the adsorption on the internal wall. The energy diagram of such various adsorptions were found to be governed by the pore size, radius of curvature, of zeolites. The double bond shift of 1-butene to 2-butene was observed below 230K on ZSM-5 and mordenite (MOR) as a result of intramolecular reaction, where the protons on the acidic OH groups were not involved in the reactant (2-butene). The initial intermolecular reaction of the formed 2-butene as well as isobutene terminated once at dimerization, and further reactions did not occur at room temperature, differently from the case of ethane and propene. Further studies, which are presently proceeding, and the prospective are also mentioned.